261479381 has 2 divisors, whose sum is σ = 261479382. Its totient is φ = 261479380.

The previous prime is 261479287. The next prime is 261479437. The reversal of 261479381 is 183974162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188650225 + 72829156 = 13735^2 + 8534^2 .

It is a cyclic number.

It is not a de Polignac number, because 261479381 - 2¹⁸ = 261217237 is a prime.

It is a super-3 number, since 3×261479381³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261475381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130739690 + 130739691.

It is an arithmetic number, because the mean of its divisors is an integer number (130739691).

Almost surely, 2^261479381 is an apocalyptic number.

It is an amenable number.

261479381 is a deficient number, since it is larger than the sum of its proper divisors (1).

261479381 is an equidigital number, since it uses as much as digits as its factorization.

261479381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 41.

The square root of 261479381 is about 16170.3240845692. The cubic root of 261479381 is about 639.4586739368.

The spelling of 261479381 in words is "two hundred sixty-one million, four hundred seventy-nine thousand, three hundred eighty-one".